The Straight Crenellation Assortment Pack is part of the Castle Builder System. It is made of "Dwarvenite". This item was initially available as an add-on to a pledge level during the Castle Builder System Kickstarter. The item comes in both painted and unpainted versions.
The Straight Crenellation Assortment Pack comes with these 20 pieces:
(4) Rampart Crenellation
(4) High Crenellated Corner
(4) Oil Cauldron
(2) Battlements Transition - Left
(4) Accessory Slot Crenellation
(2) Battlement Transition - Right